| Chemical Abstract Number (CAS #) |
118741 |
| Synonyms |
Hexachlorobenzene |
| HCB |
| Benzene, hexachloro- |
| Analytical Methods |
EPA Method 505 EPA Method 508 EPA Method 525 EPA Method 612 EPA
Method 625 EPA Method 8081 EPA Method 8120A EPA Method 8250A |
| Molecular Formula |
C6Cl6 |
| Use |
IN ORGANIC SYNTHESES AS A RAW MATERIAL FOR SYNTHETIC
RUBBER; PLASTICIZER FOR POLYVINYL CHLORIDE; AS A
RUBBER PEPTIZING AGENT IN THE MANUFACTURE OF NITROSO
AND STYRENE-TYPE RUBBERS ADDITIVE FOR PYROTECHNIC
COMPOSITIONS FOR THE MILITARY, POROSITY
CONTROLLER IN MANUFACTURE OF ELECTRODES; INTERMEDIATE IN DYE
MANUFACTURE. A SELECTIVE FUNGICIDE SUGGESTED FOR SEED
TREATMENT OF WHEAT AGAINST BUNT (TILLETIA TRITICI)
FOUND EFFECTIVE FOR CONTROL OF DWARF BUNT.
ATTRIBUTE CONTROL TO INHIBITORY ACTION OF VAPOR ON
SPORE GERMINATION. FUNGICIDE FOR CONTROL OF SMUT ON
GRAIN, ESP WHEAT CHEM INTERMEDIATE. EG, FOR DYES & HEXAFLUOROBENZENE
Manufacture of pentachlorophenol, wood preservative; used in the
production of aromatic fluorocarbons; used to
impregnate paper Fungicide on sunflowers (seed treatment), seedborne
diseases, insects; safflower (seed treatment),
seed and seedling diseases, and wireworms. In Europe, hexachlorobenzene
has been used as the precursor for pentachlorophenol, though not
in the USA. European pentachlorophenol made using
alkaline hydrolysis of hexachlorobenzene has more
polychlorinated dibenzo-p-dioxin and dibenzofuran impurities than the
USA pentachlorophenol product. |
| Apparent Color |
NEEDLES FROM BENZENE-ALCOHOL; White needles
|
| Boiling Point |
323-326 DEG C
|
| Melting Point |
231 DEG C
|
| Molecular Weight |
284.80
|
| Density |
1.5691 at 23.6 deg C
|
| Environmental Impact |
Hexachlorobenzene (HCB) is formed as a waste product
in the production of several chlorinated
hydrocarbons and is a contaminant in some pesticides. It may enter the
environment in air emissions and waste water in
connection with the above and in flue gases and fly ash from
waste incineration. Non-point source dispersal of
hexachlorobenzene results from its presence as a
contaminant in pesticides. HCB is a very persistent environmental
chemical due to its chemical stability and
resistance to biodegradation. If released to the atmosphere, HCB will
exist primarily in the vapor phase and
degradation will be extremely slow (estimated half-life with hydroxyl
radicals is 2 years). Long range global transport is
possible. Physical removal from the atmosphere
can occur via washout by rainfall and dry deposition. If released to
water, HCB will significantly partition from the
water colum to sediment and suspended matter. Volatilization from the
water column is rapid; however, the strong
adsorption to sediment can result in long periods of
persistence. If released to soil, HCB will be strongly
adsorbed and not generally susceptible to
leaching. Hexachlorobenzene will bioconcentrate in fish and enter into
the food chain (has been detected in food during
market basket surveys). Human exposure will be from ambient air,
contaminated drinking water and food, as well as contact
with contaminated soil or occupational
atmospheres. |
| Environmental Fate |
TERRESTRIAL FATE: HCB released to soil is likely to
remain there for extended periods of time due to
its strong adsorption to soil (a half-life of 1530 days has been
reported). Little biodegradation will occur and
transport to groundwater is expected to be slow, depending
upon the organic carbon content of the soil; some
evaporation from surface soil to air may occur,
the extent of which is dependent upon the organic content of the
soil(1,SRC). AQUATIC FATE: HCB released to water will evaporate rapidly
(half-life of ca 8 hrs has been measured in the
laboratory, adsorb to sediments and bioconcentrate in fish and other
aquatic organisms. Hydrolysis and biodegradation
will not be significant processes in water .
ATMOSPHERIC FATE: HCB released to the atmosphere can exist in both the
vapor phase and adsorbed-phase; however,
monitoring studies have demonstrated that the vapor phase should
strongly dominate . Degradation of HCB in the atmosphere
appears to be extremely slow (estimated half-life
with hydroxyl radicals is 2 years). Long range global transport is
possbile and has been observed . Physical removal
of HCB from the atmosphere to aquatic and soil
environments is possible via washout by rainfall and by dry deposition.
|
| Drinking Water Impact |
DRINKING WATER: 3 cities - Canada 0.06-0.2 parts per
trillion, mean 0.1 parts per trillion . SURFACE
WATER: Niagara Falls dumpsite-water and sediment draining into Niagara
River 8-30 ppm ; Great Lakes 0.02-0.1 parts per
trillion ; Lake Erie 4 of 5 sites pos, 0-0.04 parts
per trillion ; USA industrialized river avg . SEAWATER:
Mediterranean Sea coastal water Italy 16% pos 0.002 to 0.01 ppb .
RAINWATER: Great Lakes 1-4 parts per trillion , North Pacific - 0.03
parts per trillion , Lakes Superior 2.8 parts per
trillion . Southern North Sea: 0.002-0.02 ng/l in solution and 0.01-6.0
ng/g in suspended particles . Mediterranean Sea
near Egypt (1982-3): 0.1-12.6 ng/l . EFFL: Wastewater effluent -
nonferrous metals manufacturing 26 samples, 2 pos 220 ppb
max . Wastewater from four Canadian plants - 1-2 ppt,
1.5 ppt mean . Geismar, LA - pond and ditch water
on an industrial site - 170-75,000 ppb . Hexachlorobenzene has been
detected in fly ash and effluenet gases released from municipal
refuse incinerators and other combustion
facilities-levels in flue gas ranged from 9.5 ng/cu m to 11
ug/cu m(1,2,3,4). |
